Fuel pump



Oct. 12, 1937. M. J. KITTLER 2,095,475

r FUEL PUMP Filed April 29, 1935 2 Sheets-Sheet 2 ML 70 m- INVENTOR I Patented oer. 12, 1937 FUEL PUMP Milton J. Kittler, Detroit, Mich, assignoi' m Milton E. Chandler, Detroit, Mich.

Application April 29, 1935, Serial No. 18,714

Claims. (Cl. 103-44) This invention relates to a fuel supply system for an automobile or airplane in which the fuel pump is located'on the tank and where the operating means for the fuel pump consist of a pulsating column of liquid. This column of liquid is caused to pulsate by means of a pulsator operatively connected to the engine.

The object of the invention is to insure that the fuel supply from the tank to the carburetor at all times is under pressure. The difiiculty, if the fuel supply is under suction, is that when the fuel pump is not in use a certain amount of vapor is released, especially when the weather is warm and when highly volatile fuel is used. On starting the engine more vapor is released due to the drop in pressure. The" result .of this is that the fuel pump actually handles as much vapor as it does liquid fuel. This vapor constitutes a fire hazard as it escapes from the vents in the float chambers and is highly inflammable. Moreover, it causes the fuel mileage to be lower than it otherwise would beif this vapor were not.

wasted.

. Figure I of the drawings herewith shows diagrammatically the arrangement of the fuel pump 25 on the tank and the pulsator on theengine.

' Figure 2 shows in cross-sectional elevation the constructional details of the preferred form of my invention.

Figure 3 shows an alternative arrangement in which a piston is substituted for the diaphragm. Figure 4 shows means for packing the pulsator. Figure 5 shows a plan view taken on plane 5--5 of Figure 3.

Figure 6 shows the addition of a vapor' dome to 35 the outlet pipe to prevent water hammer in the fuel supply pipe and to maintain a steady flow to the carburetor.

in the figures, A is the engine, B is the pulsator operated by a cam which is mounted on the cam 40 shaft. The piflsator B comprises a piston D shown in its mid stroke position on the camC. A

spring E causes the piston D to ride in contact with this cam C. A pipe F supplies fuel to a carburetor or to a fuel injection system as the case may be. G is the fuel pipe connecting the fuel pump H with the pulsator'B. The fuel pump H which is mounted on a tank J comprises a flexible diaphragm K bolted between a casting L 50 containing the fuel pump entrance and a casting M containing the fuel pump exit. An automatic inlet valveN is provided through an opening in the center of the flexible diaphragm K. which diaphragm is supported by the spring 0 which is seated uponthe fuel entrance casting L. The

valve N is supported-by a light spring P. The diaphragm K is deflected by a. free piston Q which slides inside the casting M.- Thispiston Q is provided with an outlet passage controlled by the automatic valve R supported by alight spring 5 S. The free piston Q engages with the diaphragm K by means of the piece T which is bolted to the center of the diaphragm li and in which is mounted the fuel inlet valve N and the spring P. Fuel passages communicate through the piston Q and through the piece T so that fuel can flow through the inlet valve N and out through the valve R as they are alternately opened and closed by the reciprocation of the piston Q and the corresponding flexing of the V diaphragm K. A by-pass passage U is provided in the casting M to provide an alternative path to that past R for the fuel tofiow from K to G. This by-pass U is closed by the piston Q when the piston Q is in its mid position and thereafter as Q moves over to the left under the influence of the spring 0. When the piston Q is oscillating,

' and in fact the moment'the piston Q moves from the'mid position in which it is shown, over to the right, this by-pass U is uncovered gradually permitting the full pressure generated by the pulsator B to be applied to the diaphragm K so that the energy developed by the pulsator D is stored up in the spring 0 so as to be available for pumping fuel as described below.

Figure 3 shows an alternative construction in which a light .piston V takes the place of the diaphragm K, but the function of the inlet valve N and the outlet valve R remains as before.

In Figure 4 a packing Y is addedto the piston D and a spring loaded packing W is added to the pulsator B to eliminate leakage as a factor. In all cases a fuel port Xforming the outlet from the pulsator B'is provided and is so located so as to be completely covered when the piston D is in 40 the middle of its stroke and to be gradually .uncovered as the piston D descends on its suction stroke.

Operation.-When the pulsator piston D is moving up and down the gasoline in the pipe G 4 pulsates in step with the pulsation of the piston D. This liquid column causes the free piston Q also to pulsate and hence the diaphragm K moves in synchronism with the piston D. When K moves over to the right the volume of liquid trapped between Q and K increases; hence, liquid flows mt the valve N through the piece T until the piston Q reaches the mid position in which it is shown (Figure 2) when the by-pass U is uncovered thereupon the full pressure of the fuel in the pipe G acts on the diaphragm K and the energy of the pulsator is stored up in the compression of the spring 01 When the piston D descends the spring moves the diaphragm K and the piston Q over to the left. The piston '53 then once more covers the lay-pass U. The fuel in G is then trapped and as the piston D continues to descend, fuel is forced through the piston Q and through the port X into the fuel feed pipe F by the energy stored in the spring 0. The diaphragm K forces gasoline through G, out X, into F and a certain quantity of gasoline is thus fed to the engine A when the float mechanism of the carburetor permits. Therefore, for each cycle of the piston D a definite quantity of gasoline is added to the pipe F if required. It will be noticed that the pressure of this fuel is determined by the stiffness of the spring 0, hence an excessive supply of fuel is avoided by selecting the right spring 0.

In Figure 6 a vapor dome Z is added to prevent water hammer and to maintain the pressure in the line F between impulses so as to insure a. steady flow to the engine carburetor.

The operation, with special reference to th function of the by-pass U, is as follows:-

The icy-pass U is mainly operative when flow through the pipe F is very small, or zero.. Under these circumstances each impulse of the piston I) would cause a filling stroke of the diaphragm K and would ultimately result in its breakage if no fuel were discharged through the pipe F. In the construction shown, when the piston Q has been displaced sumciently far to expose the bypass U, any further impulses oi. the piston D serve merely to shuttle the fuel between the unit B and the unit H, as no filling of the pumping chamber can take place while the by-pass U is exposed.

What I claim is: l. A fuel supply system comprising an engine, a fuel supply means mounted thereon, a pipe connected to said means, a fuel cylinder mounted on the engine, a piston therein, engine driven means for reciprocating said piston, a. port in the wall aspects of the cylinder adapted to be closed when the piston is at the end of its in stroke, said port communicating with said pipe, 2. fuel tank, a second pipe connecting said cylinder to said fuel tank, a fuel chamber mounted on said tank, said fuel chamber being provided with a yielding wall, resilient means therefor, a cylinder in said chamher, a second piston mounted therein engaging with said yielding wall, the space between said piston and said wall constituting said fuel cham-- her, a non-return vaveadmitting fuel from said tank to said fuel chamber, a second non-return valve adapted to discharge fuel from said fuel chamber to said second pipe for the purpose described.

2. A fuel supply system as in claim 1 with a bypass'ieading from the fuel chamber to saidsecond pipe adapted to be uncovered by said second piston when both of said pistons are at the end of their in stroke.

3. A fuel supply system as in claim 1 with a by-pass leading from the fuel chamber to said second pipe adapted to be uncovered by said second piston when said first piston is at the end of its in stroke.

4. A fuel supply system comprising an engine, a fuel feeding device therefor mounted therein, a fuel supply tank, a fuel chamber associated therewith having flexible wall and a cylindrical opening, a piston in said opening, said fuel chamher being bounded by said wall and said piston, resilient "means for pressing said wall against said piston, a pipe connecting said cylindrical opening with said fuel feeding device, engine driven means for creating pulsation in said pipe whereby the piston, wall and spring are caused to reciprocate together, a check valve adapted to admit fuel from the tank to the fuel chamber, a. second check valve to permit fuel to escape therefrom to said pipe.

5. A fuel supply system as in claim 4 with a by-pass leading from the fuel chamber to said 

